Side-folding airplanes arresting gear

ABSTRACT

An airplane arresting gear has a generally planar frame (20) having a front end and a rear end that is adapted to be attached at the front end to a structure of the airplane for pivotal movement about a frame pivot axis (FPA) substantially parallel to the airplane z-axis between a stowed position in which the frame (20) resides within the fuselage skin and a deployed position in which the frame (20) extends rearwardly and obliquely downwardly with respect to the x-axis of the airplane. A shank (30) having a cable hook (80) at the rear end is coupled at its front end to the rear end of the frame (20) for pivotal movement about a shank pivot axis between a deployed position in which the shank (30) extends rearwardly from the shank pivot axis and a stowed position in which the shank (30) extends generally forwardly from the shank pivot axis and lies abreast of the frame (20). A deploying damper-actuator (70), which is coupled between the frame (20) and the structure of the airplane moves the frame (20) from the stowed position to the deployed position. A retractor actuator (92), which is likewise coupled between the frame (20) and the structure of the airplane, moves the frame (20) from the deployed position to the stowed position. An actuator mechanism (74), which is connected between the frame (20) and the shank (30), moves the shank (30) between the deployed and stowed positions. An up-swing damper (52) prevents the frame/shank unit (10) from contacting the fuselage.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to the field of aircraft arresting gear and, in particular, to a side-folding airplane arresting gear.

BACKGROUND OF THE INVENTION

The arresting gear for an airplane that lands in a very short distance and is stopped by an arresting cable, such as a carrier-based airplane, conventionally includes a tail hook in the form of a unitary, relatively long, arm that is attached by a pivot coupled to a keel member, or a pair of keel members, of the airframe. The tail hook is generally stowed in an upper position either closely adjacent and outside of the skin of the underside of the fuselage or within a cavity in the skin. The tail hook swings down to a deployed position in which a hook on the end of the arm can be caught by an arresting cable. Conventional long arm tail hooks, which may include a damper and a deployment mechanism, generally require a long space within the skin.

The front end of a conventional long arm tail hook is generally attached to the airframe at a point relatively far forward of the rearmost end of the fuselage so that the rear end of the tail hook, when stowed, will not extend beyond the tail end of the fuselage. For airplanes having a single tail engine, such as many carrier-based fighters, the long arm tail hook can interfere with removal of the engine and often must be removed before the engine can be removed.

It is desirable to minimize the load placed on the nose gear of the aircraft during an arrested landing. The vertical location of the tail hook attachment to the airframe determines the loads generated by the arresting cable on the nose gear of the airplane during an arrested landing. In an arrested landing of an airplane, the load created by the arresting cable runs generally from the arresting cable through the attachment point of the tail hook to the airplane. Airplanes having a conventional arresting gear are generally attached at a point on the airframe vertically below the center of gravity. The low vertical attachment of the conventional arresting gear places a large vertical load on the nose gear, because the load line created by the arresting cable passes far below the center of gravity of the airplane.

Modern fighters may require the arresting gear to be enclosed within doors that open to allow the arresting gear to deploy. Many arresting gear configurations are unsuitable to provide this requirement since the closures would be at risk of damage by the cable or arresting hook during an arrestment with the doors opened.

SUMMARY OF THE INVENTION

Accordingly, a need has arisen for an improved arresting gear for an airplane. The present invention provides side-folding airplane arresting gear that substantially eliminates or reduces problems associated with the prior methods and systems.

In accordance with one embodiment of the present invention, a side-folding airplane arresting gear includes a generally planar frame that is adapted to be attached at its front end to a structure of the airplane for pivotal movement about a frame pivot axis parallel to the airplane y-axis between a stowed position in which the frame resides generally parallel to a horizontal plane defined by the x-axis and y-axis and a deployed position in which the frame extends rearwardly from the frame pivot axis and obliquely downwardly with respect to the horizontal plane. A shank having a cable hook at the rear end is coupled at its front end to the rear end of the frame for pivotal movement about a shank pivot axis that is substantially perpendicular to the frame between a deployed position in which the shank extends rearwardly from the shank pivot axis and a stowed position in which the shank extends generally forwardly from the shank pivot axis and lies abreast of the frame. A deploying damper-actuator, which is coupled between the frame and a structure of the airplane, moves the frame from the stowed position to the deployed position. A stowing actuator, which is likewise coupled between the frame and a structure of the airplane moves the frame from the deployed position to the stowed position. A shank actuator mechanism, which is connected between the frame and the shank, moves the shank between the deployed and stowed positions.

In one embodiment, a lateral damper and centering cam mechanism associated with the shank and located proximate to the pivot axis enables the shank to pivot about the shank pivot axis against a biasing force when the shank is in the deployed position. For example, the lateral damper and cam mechanism may include a centering cam member pivotally mounted for rotation about the shank pivot axis and a cam follower carried by the shank and biased into engagement with the cam member. In such an arrangement, the biased cam follower works against the cam to hold the shank substantially parallel to a vertical center plane defined by the x-axis and the z-axis of the airplane but allows the shank to pivot relative to the frame so as to lie obliquely to the vertical center plane. The lateral damper and cam mechanism functions when the x-axis of the airplane is oblique to the segment of arresting cable caught by the hook on the shank by allowing the shank to rotate. Wear of the cable and the hook are reduced, and articulation of the shank is dampened.

The lateral damper and centering cam mechanism may be associated with the actuator mechanism by which the shank is moved between the deployed and stowed positions by providing a crank arm on the cam of the lateral damper and cam mechanism. The shank actuator mechanism pivots the centering cam member, and the centering cam member pivots the shank via the cam follower.

The frame may be generally V-shaped in the plan form view and include a first arm and a second arm that are joined to each other at their rear ends and diverge outwardly from each other from the rear end toward the front end of the frame. A "V" configuration facilitates connecting the frame to parallel longitudinal keels of the frame of the airplane and provides for splitting the load of the arresting gear between the keels.

In another embodiment, the arresting gear includes an up-swing damper that is adapted to be attached to the structure of the airplane in a position to be engaged by a portion of the frame in the event that the frame/shank swings upwardly about the frame pivot axis from the deployed position to an extent that it may strike the airplane when the arresting gear operates to arrest the airplane. In a particular embodiment, the up-swing damper is adapted to be movably attached to the airplane structure, such as by pivoting, for movement between a stowed position and a deployed position. An actuator mechanism is coupled to the up-swing damper and adapted to be coupled to the structure of the airplane for moving the up-swing damper between the stowed position and the deployed position.

A movable latch member adapted to be attached to the structure of the airplane and engageable with a latch coupling on the frame when the frame is in the stowed position may be provided in association with the actuator mechanism of the up-swing damper. The latch member holds the frame/shank unit of the arresting gear in the stowed position at all times, except when the frame/shank unit is deployed, and permits the stowing actuator to be connected to the return reservoir of the hydraulic system except when it is being operated to restore the frame/shank unit from the deployed state after a landing to the stowed state. When the actuator mechanism of the up-swing damper is operated to deploy the up-swing damper, the latch member is released from engagement with the frame/shank unit, which can then be deployed by operation of the deploying damper/actuator.

Technical advantages of the present invention include providing an aircraft arresting gear that occupies a relatively short space when stowed and that is stowed entirely within the skin of the fuselage.

Another technical advantage of the present invention is that the arresting gear is attached to the airframe at a point relatively far back on the airframe as compared with conventional arresting gear, thereby reducing the loads placed on the nose gear during arrested landings of the airplane.

Another technical advantage of the present invention is that arresting gear may be enclosed within an opening in the fuselage that requires no additional actuation mechanism and has little risk of being damaged by the arresting cable during an arrested landing of the airplane.

Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, description, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and its advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, wherein like reference numerals represent like parts, in which:

FIG. 1 is a perspective view of a frame/shank unit in a stowed position in accordance with one embodiment of the present invention;

FIG. 2 is a top plan form view of the frame/shank unit of FIG. 1 in the stowed position;

FIG. 3 is a side cross-sectional view of a centering cam mechanism taken along line 3--3 of FIG. 2 in accordance with one embodiment of the present invention;

FIG. 4 is a left side elevational view of the frame/shank unit of FIG. 1 in the stowed position;

FIG. 5 is a partial top plan form view of the frame/shank unit of FIG. 1 in the deployed position and with a hook engaging an arresting cable;

FIG. 6 is a partial top plan form view of the frame/shank unit of FIG. 1 with a lateral deflection of the shank;

FIG. 7 is a left side elevational view of the frame/shank unit of FIG. 1 in the deployed position;

FIG. 8 is a schematic side elevational view of an up-swing damper mechanism in the stowed position in accordance with one embodiment of the present invention; and

FIG. 9 is a schematic side elevational view of the up-swing damper mechanism of FIG. 8 in the deployed position.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 through 9 illustrate one embodiment of an improved arresting gear for an airplane. As will be discussed in greater detail below, the arresting gear may include a frame and a shank that pivot between a deployed position in which the frame and the shank extend rearwardly and downwardly with respect to the airplane, and a stowed position in which the frame resides within the fuselage skin and the shank lies abreast of the frame. The arresting gear occupies a relatively short space when stowed and may be attached relatively far back on the airplane as compared to conventional arresting gear.

In one embodiment of the present invention, as shown in FIGS. 1 and 2, an arresting gear for an aircraft includes a frame/shank unit 10 attached by pivot mountings 12 and 14 to a supporting frame 16. The pivot mountings define a frame pivot axis FPA parallel to the y-axis of the airplane. The supporting frame 16 is affixed to structural components of the aircraft frame, such as twin longitudinal keels (not expressly shown). In an airplane with a single engine in the tail, the frame/shank unit 10 and the supporting frame 16 may be installed in an opening 65 in an engine removal door D, a portion of which is shown by phantom lines in FIGS. 2, 4, and 7. As shown in FIGS. 2 and 7, a skin panel SP is attached to the underside of the frame 20 of the unit 10. The skin panel SP substantially closes the opening 65 when the frame/shank unit 10 is in the stowed position.

The frame 20 of the frame/shank unit 10 is V-shaped in plan form view, as shown in FIGS. 1 and 2, and planar in profile, as shown in FIG. 4, with arms 22 and 24 diverging forwardly from a rear end that receives in a yoke portion 26 a pivot pin 28. The pivot pin 28 defines a shank pivot axis perpendicular to the plane of the frame 20. As shown in FIG. 3, a shank 30 is pivotally received on the pin 28 by means of an end portion 30a. The end portion 30a of the shank 30 straddles a centering cam member 32, which pivots about the pin 20 independently of the shank 30. An axially extending cavity 34 in the shank 30 receives a cam follower roller 36 on a support 38 that is biased by a spring 39 to engage the roller with a concave, centering cam surface on the cam 32.

The shank 30 is stowed abreast of the arm 22 of the frame, as shown in FIGS. 1 and 2. In the stowed configuration, the frame/shank unit 10 occupies a relatively small space, particularly in the longitudinal direction, which facilitates stowing the frame/shank unit 10 within the skin of the airplane without reducing the aerodynamic profile of the aircraft. The frame/shank unit 10 can be installed relatively close to the tail end of the airplane which, during an arrested landing, results in an arresting load line that passes near the center of gravity of the airplane, resulting in a reduced load on the nose gear as compared to conventional long arm tail hooks.

As illustrated in FIG. 8, the frame/shank unit 10 is held in the stowed position by a latch lever 40, which is pivotally mounted by a pivot pin 42 to a bracket 44 which is affixed to the structure of the airplane. Latch lever 40 is biased by a compression spring 46 to engage a latch roller 48 supported by a bracket 50 on the frame 20, and is associated with an actuator mechanism, which also operates an up-swing damper 52 having a plunger 52p. In another embodiment, the latch lever 40 may be separate from and operated independently of the up-swing damper 52.

A closed end 54c of a double-acting hydraulic piston/cylinder 54 is pivotally connected to a link 63. The link 63 is pivotally mounted by the pivot pin 42 to the bracket 44 in a similar manner as the latch lever 40. A stop 40s is fixed to latch lever 40. The piston rod 54pr is pivotally connected to one arm of a bell crank 56, which pivots about a pivot pin 58 carried by a bracket 60 which is affixed to the structure of the airplane. The other arm of the bell crank 56 is coupled to a toggle linkage 62. As shown in FIG. 9, extension of the hydraulic cylinder 54 pivots the link 63 against the stop 40s on the latch lever 40, forcing the latch lever 40 to pivot about the pivot pin 42 to a release position in which the latch roller 48 is released from a latch notch 40ln in the latch lever 40, thereby freeing the frame/shank unit 10 for deployment. When the frame/shank unit 10 returns to the stowed position, the latch roller 48 moves toward the latch notch 40ln while engaging an inclined cam edge 40ce of the latch lever 40, which pushes the latch lever 40 to its release position. In the stowed position of the frame/shank unit 10, as shown in FIG. 8, the latch roller 48 is accepted in the latch notch 40ln and the latch lever 40 is forced to the latched position by the compression spring 46, holding the latch roller 48 within the latch notch 40ln.

When the frame/shank unit 10 is released from the latched condition, the frame/shank unit 10 is lowered to its deployed position by its own weight and by pneumatic pressure supplied by a deploying damper-actuator 70 connected between the supporting frame 16 and a crank arm 72 affixed to the arm 22 of the frame 20. Extension of the deploying damper-actuator 70 pivots the frame/shank unit 10 about the frame pivot axis FPA so that the frame/shank unit 10 extends obliquely downwardly with respect to the horizontal plane created by the x-axis and y-axis of the airplane.

The sequence of the deployment of the arresting gear is mechanically controlled. Hydraulic pressure with pneumatic pressure backup may be simultaneously and continuously applied to extend the up-swing damper 52 and to unfold the shank 30, which are momentarily prevented until the frame/shank unit 10 begins to lower. As shown in FIG. 2, a vertical guide 64 attached to the engine removal door D prevents the shank 30 from unfolding until the frame/shank unit 10 deploys. As the frame/shank unit 10 deploys, the shank 30 drops below the vertical guide 64, allowing the shank 30 to unfold. In addition, as shown in FIG. 9, when the frame/shank unit 10 deploys, the upswing damper 52 is allowed to extend to its deployed position.

In the stowed position of the shank 30, as shown in FIG. 2, the piston rod 74pr is extended. A hydraulic shank actuator 74 is connected between the arm 24 of the frame 20 and a folding linkage 76. The actuator 74 is of a known type that locks in the retracted position. When the hydraulic actuator 74 forces piston rod 74pr to retract, the linkage 76 is pulled about the pivot point 76p, applying a force to a crank arm 32ca on the centering cam 32. The shank 30 is pivoted about the pivot pin 28 to its deployed position in which the shank 30 lies substantially parallel to the plane created by the x-axis and the z-axis of the airplane and rearwardly from the frame 20, as shown in FIGS. 5 and 7. Rotation of the centering cam 32 by the actuator 74 and linkage 76 is transmitted to the shank 30 by the damping and centering cam mechanism, the cam follower roller 36 being held centered in the deepest part of the concave cam surface of the cam member 32 by the spring 39.

In the fully deployed position, as illustrated in FIGS. 5 and 7, the frame/shank unit 10 of the arresting gear extends downwardly and rearwardly from the frame pivot axis FPA and positions a cable hook 80 on the rear end of the shank 30 for capture by an arresting cable AC at the landing site of the airplane.

If the load line created by the arresting cable AC on the shank 30 during an arrested landing does not lie within the plane created by the x-axis and z-axis of the airplane, the force applied to the shank 30 by the cable AC will have a lateral component. As shown in FIG. 6, the lateral damping and centering cam mechanism permits the shank 30 to articulate about the pivot pin 28, the articulation being damped by the cam follower spring 39, which is compressed as the follower roller 36 is deflected by the cam surface of the centering cam 32.

After the arresting cable AC captures the hook 80 on the shank 30 and the airplane lands, the frame/shank unit 10 will swing upwardly. Simultaneous with deployment of the frame/shank unit 10, as described above, the up-swing damper 52 is deployed from the stowed position, as shown in FIG. 8, to the deployed position, as shown in FIG. 9. Extension of the piston rod 54pr of the actuator 54 pivots the bell crank 56 about the pivot pin 58, the damper 52 pivots so that the plunger 52p extends downwardly, and straightens the toggle linkage 62, locking the damper 52 in the deployed position. If the frame/shank unit 10 swings excessively upward, the frame 20 will strike the damper 52, which absorbs the impact and prevents any part of the frame/shank unit 10 from striking the fuselage. In a severe upswing, an elastomeric bumper pad 90 on the shank 30 contacts the fuselage and prevents or minimizes damage.

The deploying damper-actuator 70 of the frame/shank unit 10 is of a type that includes a pneumatic accumulator (not expressly shown) for damping and for normal and emergency operation. Upon unlatching of the latch lever 40, the unit 10 is deployed by gravity and by gas pressure applied by the accumulator/damper mechanism (not expressly shown) of the deploying damper-actuator 70, which delivers hydraulic fluid to the piston/cylinder mechanism (not expressly shown) of the deploying damper-actuator 70. Similarly, the actuator 54 for the up-swing damper 52 and the shank-deploying actuator 74 have a pneumatic system associated with a hydraulic supply. The pneumatic system provides a backup in the event of a failure of the hydraulic system. Indicator switches are associated with the frame 20, the shank 30, and the up-swing damper 52 to provide for the generation of electrical signals indicative of the status of those parts for use in providing visible and/or audible indications to the pilot and to provide an arresting gear electrical control system. Such signaling systems are ubiquitous in aircraft and can be designed by those of ordinary skill in the art, and are therefore not described or shown.

After the aircraft comes to a rest and the arresting cable AC is released from the hook 80, the up-swing damper 52 is restored to the stowed position, as shown in FIG. 8, by operation of the actuator 54, the shank 30 is swung back to the stowed position abreast of the frame 20, as shown in FIGS. 1, 2, and 4, by operation of the shank actuator 74, and the frame/shank unit 10 is raised up to the stowed position by a stowing actuator 92, which is connected between the support frame 16 and a crank arm 94 affixed to the arm 24 of the frame 20. The actuator 92 includes a single-acting hydraulic piston/cylinder and a control valve (not expressly shown) that routes hydraulic fluid to the cylinder to retract the piston rod, which pulls the frame 20 and the stowed shank 30 upwardly. When the stowing actuator 92 operates and the frame/shank unit 10 is lifted back to the stowed position, the hydraulic fluid in the deploying damper-actuator 70 is forced back into the fluid side of the pneumatic accumulator.

Near the end of the return of the frame/shank unit 10 to the stowed position, the latching roller 48 engages the inclined cam surface 40ce of the latch lever 40. Further upward movement of the frame/shank unit 10 forces the lever 40 to pivot against the biasing compression spring 46, thus allowing the roller 48 to move up along the cam surface 40ce and ultimately be accepted in the latch notch 40ln. When the frame/shank unit 10 is latched in the stowed position, the stowing actuator 92 valve is cycled back to its normal mode, in which both the pressure and return sides are connected to the return side, or reservoir, of the hydraulic system. Accordingly, when the arresting gear is to be deployed, the stowing actuator 92 is dormant and its piston/cylinder is free to extend in relation to the deploying damper-actuator 70.

Although the present invention and its advantages have been described in accordance with one embodiment, various changes, modifications, and substitutions may be suggested to one skilled in the art. It is intended that the present invention encompass such changes, modifications, and substitutions that fall within the scope of the appended claims. 

What is claimed is:
 1. Arresting gear for an airplane, the airplane having a longitudinal x-axis and a lateral y-axis perpendicular to and intersecting the x-axis, wherein the x-axis and y-axis define a substantially horizontal plane, the arresting gear comprising:a generally planar frame having a front end and a rear end and being adapted to be attached at the front end to a structure of the airplane for pivotal movement about a frame pivot axis substantially parallel to the y-axis between a stowed position in which the frame resides generally parallel to the horizontal plane and a deployed position in which the frame extends rearwardly from the frame pivot axis and obliquely downward with respect to the horizontal plane; and a shank having a front end and a rear end with a cable hook at the rear end, the shank being coupled at its front end to the rear end of the frame for pivotal movement about a shank pivot axis, between a deployed position in which the shank extends rearwardly from the shank pivot axis and a stowed position in which the shank extends generally forwardly from the shank pivot axis and lies abreast of the frame.
 2. Arresting gear according to claim 1 and further comprising a deploying damper-actuator coupled to the frame and adapted to be coupled to the structure of the airplane and operable to move the frame from the stowed position to the deployed position.
 3. Arresting gear according to claim 1 and further comprising a stowing actuator coupled to the frame and adapted to be coupled to the structure of the airplane and operable to move the frame from the deployed position to the stowed position.
 4. Arresting gear according to claim 1 and further comprising means coupled between the frame and the shank for moving the shank between the deployed and stowed positions.
 5. Arresting gear according to claim 1 and further comprising a lateral damper and centering cam mechanism associated with the shank and adapted to enable the shank to pivot about the shank pivot axis against a biasing force.
 6. Arresting gear according to claim 5 wherein the lateral damper and centering cam mechanism includes a centering cam member pivotally mounted for rotation about the shank pivot axis and a cam follower carrier by the shank and biased into engagement with the cam member.
 7. Arresting gear according to claim 1 wherein the frame is generally V-shaped in plan form view and includes a first and a second arm that are joined to each other at their rear ends and diverge outwardly from each other from the rear end toward the front end of the frame.
 8. Arresting gear according to claim 1 and further comprising means coupled between the frame and the shank for moving the shank between the stowed and deployed positions, and a lateral damper and centering cam mechanism associated with the shank and adapted to enable the shank to pivot against a biasing force.
 9. Arresting gear according to claim 1 and further comprising a skin panel attached to the frame, the skin panel substantially enclosing the arresting gear within a opening in the airplane when the frame is in the stowed position.
 10. Arresting gear according to claim 1 and further comprising an up-swing damper adapted to be attached to the structure of the airplane in a position to be engaged by the frame to prevent the arresting gear in the deployed position from swinging upwardly about the frame pivot axis to an extent that it would strike the airplane.
 11. Arresting gear according to claim 10 wherein the up-swing damper is adapted to be movably attached to the airplane structure for movement between a stowed position and a deployed position and further comprising means coupled to the up-swing damper and adapted to be coupled to the structure of the airplane for moving the up-swing damper between the stowed position and the deployed position.
 12. Arresting gear according to claim 11 wherein the means for moving the up-swing damper between the stowed position and the deployed position includes a movable latch member adapted to be attached to the structure of the airplane and engageable with a latch coupling on the frame when the frame is in the stowed position.
 13. Arresting gear according to claim 1 and further comprising:means coupled between the frame and the shank for moving the shank between the deployed and stowed positions comprising: a lateral damper and a centering cam mechanism having a centering cam member mounted on the frame for pivotal movement about the shank pivot axis; a cam follower movably carried by the shank and biased into engagement with the centering cam member; a crank arm coupled to the centering cam member; and a power actuator coupled between the frame and the crank arm, whereby the actuator pivots the centering cam member and the centering cam member pivots the shank via the cam follower.
 14. Arresting gear for an airplane, the airplane having a longitudinal x-axis and a horizontal y-axis that is perpendicular to the x-axis, wherein the x-axis and y-axis define a substantially horizontal plane, the arresting gear comprising:a generally planar frame having a front end and a rear end, the frame being generally V-shaped in plan form view and having first and a second arm that are joined to each other at the rear end of the frame and diverge outwardly from each other from the rear end toward the front end of the frame, the frame being adapted to be attached at the front end to a structure of the airplane for pivotal movement about a frame pivot axis between a stowed position in which the frame resides generally parallel to the horizontal plane, and a deployed position in which the frame extends downwardly and rearwardly from the frame pivot axis and obliquely with respect to the horizontal plane; means coupled to the frame and adapted to be coupled to a structure of the airplane for moving the frame between the stowed position and the deployed position; a shank having a front end and a rear end with a cable hook at the rear end, the shank being attached at its front end to the rear end of the frame for pivotal movement about a shank pivot axis for movement of the shank between a deployed position in which the shank extends generally rearwardly from the shank pivot axis, and a stowed position in which the shank extends generally forwardly from the shank pivot axis and lies abreast of the frame; an operating linkage coupled to the shank; and a power actuator coupled between the linkage and the frame, the linkage and actuator being operable to move the shank between the stowed and deployed positions.
 15. Arresting gear according to claim 14 wherein the linkage includes a lateral damper and centering cam mechanism, the lateral damper and cam mechanism being adapted to enable the shank to pivot about the shank pivot axis against a biasing force.
 16. Arresting gear according to claim 15 wherein the lateral damper and cam mechanism includes a centering cam member pivotally mounted for rotation about the shank pivot axis and a cam follower carried by the shank and biased into engagement with the cam member.
 17. Arresting gear according to claim 14 and further comprising an up-swing damper adapted to be attached to the structure of the airplane in a position to be engaged by the frame to prevent the arresting gear in the deployed position from swinging upwardly about the frame pivot axis to an extent that it would strike the airplane.
 18. Arresting gear according to claim 17 wherein the up-swing damper is adapted to be movably attached to the airplane structure for movement between a stowed position and a deployed position and further comprising means coupled to the up-swing damper and adapted to be coupled to the structure of the airplane for moving the up-swing damper between the stowed position and the deployed position.
 19. Arresting gear according to claim 18 wherein the means for moving the up-swing damper between the stowed position and the deployed position includes a movable latch member adapted to be attached to the structure of the airplane and engageable with a latch coupling on the frame when the frame is in the stowed position.
 20. Arresting gear according to claim 14 wherein the linkage comprises:a lateral damper and cam mechanism including a centering cam member mounted on the frame for pivotal movement about the shank pivot axis and a cam follower movably carried by the shank and biased into engagement with the centering cam member; and means for moving the shank between the deployed and stowed positions including a crank arm affixed to the centering cam member and a power actuator coupled between the frame and the crank arm, whereby the actuator pivots the centering cam member and the centering cam member pivots the shank via the cam follower. 